[NaaS] Add cel list extension function in the NaaS evaluator.

PiperOrigin-RevId: 775290530

Author: CEL Dev Team

extensions/BUILD

@@ -347,8 +347,12 @@ cc_library(
     srcs = ["lists_functions.cc"],
     hdrs = ["lists_functions.h"],
     deps = [
+        "//checker:type_checker_builder",
+        "//checker/internal:builtins_arena",
+        "//common:decl",
         "//common:expr",
         "//common:operators",
+        "//common:type",
         "//common:value",
         "//common:value_kind",
         "//internal:status_macros",
@@ -360,6 +364,7 @@ cc_library(
         "//runtime:function_registry",
         "//runtime:runtime_options",
         "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/base:no_destructor",
         "@com_google_absl//absl/base:nullability",
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/status",
@@ -377,9 +382,13 @@ cc_test(
     srcs = ["lists_functions_test.cc"],
     deps = [
         ":lists_functions",
+        "//checker:standard_library",
+        "//checker:validation_result",
         "//common:source",
         "//common:value",
         "//common:value_testing",
+        "//compiler",
+        "//compiler:compiler_factory",
         "//extensions/protobuf:runtime_adapter",
         "//internal:testing",
         "//internal:testing_descriptor_pool",

extensions/lists_functions.cc

@@ -21,6 +21,7 @@
 #include <vector>
 
 #include "absl/base/macros.h"
+#include "absl/base/no_destructor.h"
 #include "absl/base/nullability.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/status/status.h"
@@ -29,8 +30,12 @@
 #include "absl/strings/string_view.h"
 #include "absl/types/optional.h"
 #include "absl/types/span.h"
+#include "checker/internal/builtins_arena.h"
+#include "checker/type_checker_builder.h"
+#include "common/decl.h"
 #include "common/expr.h"
 #include "common/operators.h"
+#include "common/type.h"
 #include "common/value.h"
 #include "common/value_kind.h"
 #include "internal/status_macros.h"
@@ -48,6 +53,8 @@
 namespace cel::extensions {
 namespace {
 
+using ::cel::checker_internal::BuiltinsArena;
+
 // Slow distinct() implementation that uses Equal() to compare values in O(n^2).
 absl::Status ListDistinctHeterogeneousImpl(
     const ListValue& list,
@@ -525,6 +532,68 @@ absl::Status RegisterListSortFunction(FunctionRegistry& registry) {
   return absl::OkStatus();
 }
 
+const Type& ListIntType() {
+  static absl::NoDestructor<Type> kInstance(
+      ListType(BuiltinsArena(), IntType()));
+  return *kInstance;
+}
+
+const Type& ListTypeParamType() {
+  static absl::NoDestructor<Type> kInstance(
+      ListType(BuiltinsArena(), TypeParamType("T")));
+  return *kInstance;
+}
+
+absl::Status RegisterListsCheckerDecls(TypeCheckerBuilder& builder) {
+  CEL_ASSIGN_OR_RETURN(
+      FunctionDecl distinct_decl,
+      MakeFunctionDecl("distinct", MakeMemberOverloadDecl(
+                                       "list_distinct", ListTypeParamType(),
+                                       ListTypeParamType())));
+
+  CEL_ASSIGN_OR_RETURN(
+      FunctionDecl flatten_decl,
+      MakeFunctionDecl(
+          "flatten",
+          MakeMemberOverloadDecl("list_flatten_int", ListType(), ListType(),
+                                 IntType()),
+          MakeMemberOverloadDecl("list_flatten", ListType(), ListType())));
+
+  CEL_ASSIGN_OR_RETURN(
+      FunctionDecl range_decl,
+      MakeFunctionDecl(
+          "lists.range",
+          MakeOverloadDecl("list_range", ListIntType(), IntType())));
+
+  CEL_ASSIGN_OR_RETURN(
+      FunctionDecl reverse_decl,
+      MakeFunctionDecl(
+          "reverse", MakeMemberOverloadDecl("list_reverse", ListTypeParamType(),
+                                            ListTypeParamType())));
+
+  CEL_ASSIGN_OR_RETURN(
+      FunctionDecl slice_decl,
+      MakeFunctionDecl(
+          "slice",
+          MakeMemberOverloadDecl("list_slice", ListTypeParamType(),
+                                 ListTypeParamType(), IntType(), IntType())));
+  // TODO(uncreated-issue/83): Update to specific decls for sortable types.
+  CEL_ASSIGN_OR_RETURN(
+      FunctionDecl sort_decl,
+      MakeFunctionDecl("sort",
+                       MakeMemberOverloadDecl("list_sort", ListTypeParamType(),
+                                              ListTypeParamType())));
+
+  CEL_RETURN_IF_ERROR(builder.AddFunction(std::move(distinct_decl)));
+  CEL_RETURN_IF_ERROR(builder.AddFunction(std::move(flatten_decl)));
+  CEL_RETURN_IF_ERROR(builder.AddFunction(std::move(range_decl)));
+  // MergeFunction is used to combine with the reverse function
+  // defined in strings extension.
+  CEL_RETURN_IF_ERROR(builder.MergeFunction(std::move(reverse_decl)));
+  CEL_RETURN_IF_ERROR(builder.AddFunction(std::move(slice_decl)));
+  return builder.AddFunction(std::move(sort_decl));
+}
+
 }  // namespace
 
 absl::Status RegisterListsFunctions(FunctionRegistry& registry,
@@ -545,4 +614,8 @@ absl::Status RegisterListsMacros(MacroRegistry& registry,
   return registry.RegisterMacros(lists_macros());
 }
 
+CheckerLibrary ListsCheckerLibrary() {
+  return {.id = "cel.lib.ext.lists", .configure = RegisterListsCheckerDecls};
+}
+
 }  // namespace cel::extensions

extensions/lists_functions.h

@@ -16,6 +16,7 @@
 #define THIRD_PARTY_CEL_CPP_EXTENSIONS_LISTS_FUNCTIONS_H_
 
 #include "absl/status/status.h"
+#include "checker/type_checker_builder.h"
 #include "parser/macro_registry.h"
 #include "parser/options.h"
 #include "runtime/function_registry.h"
@@ -46,6 +47,23 @@ absl::Status RegisterListsFunctions(FunctionRegistry& registry,
 absl::Status RegisterListsMacros(MacroRegistry& registry,
                                  const ParserOptions& options);
 
+// Type check declarations for the lists extension library.
+// Provides decls for the following functions:
+//
+// lists.range(n: int) -> list(int)
+//
+// <list(T)>.distinct() -> list(T)
+//
+// <list(dyn)>.flatten() -> list(dyn)
+// <list(dyn)>.flatten(limit: int) -> list(dyn)
+//
+// <list(T)>.reverse() -> list(T)
+//
+// <list(T)>.sort() -> list(T)
+//
+// <list(T)>.slice(start: int, end: int) -> list(T)
+CheckerLibrary ListsCheckerLibrary();
+
 }  // namespace cel::extensions
 
 #endif  // THIRD_PARTY_CEL_CPP_EXTENSIONS_SETS_FUNCTIONS_H_

extensions/lists_functions_test.cc

@@ -17,13 +17,18 @@
 #include <memory>
 #include <string>
 #include <utility>
+#include <vector>
 
 #include "cel/expr/syntax.pb.h"
 #include "absl/status/status.h"
 #include "absl/status/status_matchers.h"
+#include "checker/standard_library.h"
+#include "checker/validation_result.h"
 #include "common/source.h"
 #include "common/value.h"
 #include "common/value_testing.h"
+#include "compiler/compiler.h"
+#include "compiler/compiler_factory.h"
 #include "extensions/protobuf/runtime_adapter.h"
 #include "internal/testing.h"
 #include "internal/testing_descriptor_pool.h"
@@ -38,17 +43,19 @@
 #include "runtime/runtime_options.h"
 #include "runtime/standard_runtime_builder_factory.h"
 #include "google/protobuf/arena.h"
+#include "google/protobuf/descriptor.h"
 
 namespace cel::extensions {
 namespace {
-using ::cel::expr::Expr;
-using ::cel::expr::ParsedExpr;
-using ::cel::expr::SourceInfo;
 
 using ::absl_testing::IsOk;
 using ::absl_testing::StatusIs;
 using ::cel::test::ErrorValueIs;
+using ::cel::expr::Expr;
+using ::cel::expr::ParsedExpr;
+using ::cel::expr::SourceInfo;
 using ::testing::HasSubstr;
+using ::testing::ValuesIn;
 
 struct TestInfo {
   std::string expr;
@@ -273,5 +280,80 @@ TEST(ListsFunctionsTest, ListSortByMacroParseError) {
                HasSubstr("sortBy can only be applied to")));
 }
 
+struct ListCheckerTestCase {
+  const std::string expr;
+  bool is_valid;
+};
+
+class ListsCheckerLibraryTest
+    : public ::testing::TestWithParam<ListCheckerTestCase> {
+ public:
+  void SetUp() override {
+    // Arrange: Configure the compiler.
+    // Add the lists checker library to the compiler builder.
+    ASSERT_OK_AND_ASSIGN(std::unique_ptr<CompilerBuilder> compiler_builder,
+                         NewCompilerBuilder(descriptor_pool_));
+    ASSERT_THAT(compiler_builder->AddLibrary(StandardCheckerLibrary()), IsOk());
+    ASSERT_THAT(compiler_builder->AddLibrary(ListsCheckerLibrary()), IsOk());
+    ASSERT_OK_AND_ASSIGN(compiler_, std::move(*compiler_builder).Build());
+  }
+
+  const google::protobuf::DescriptorPool* descriptor_pool_ =
+      internal::GetTestingDescriptorPool();
+  std::unique_ptr<Compiler> compiler_;
+};
+
+TEST_P(ListsCheckerLibraryTest, ListsFunctionsTypeCheckerSuccess) {
+  // Act & Assert: Compile the expression and validate the result.
+  ASSERT_OK_AND_ASSIGN(ValidationResult result,
+                       compiler_->Compile(GetParam().expr));
+  EXPECT_EQ(result.IsValid(), GetParam().is_valid);
+}
+
+// Returns a vector of test cases for the ListsCheckerLibraryTest.
+// Returns both positive and negative test cases for the lists functions.
+std::vector<ListCheckerTestCase> createListsCheckerParams() {
+  return {
+      // lists.distinct()
+      {R"([1,2,3,4,4].distinct() == [1,2,3,4])", true},
+      {R"('abc'.distinct() == [1,2,3,4])", false},
+      {R"([1,2,3,4,4].distinct() == 'abc')", false},
+      {R"([1,2,3,4,4].distinct(1) == [1,2,3,4])", false},
+      // lists.flatten()
+      {R"([1,2,3,4].flatten() == [1,2,3,4])", true},
+      {R"([1,2,3,4].flatten(1) == [1,2,3,4])", true},
+      {R"('abc'.flatten() == [1,2,3,4])", false},
+      {R"([1,2,3,4].flatten() == 'abc')", false},
+      {R"('abc'.flatten(1) == [1,2,3,4])", false},
+      {R"([1,2,3,4].flatten('abc') == [1,2,3,4])", false},
+      {R"([1,2,3,4].flatten(1) == 'abc')", false},
+      // lists.range()
+      {R"(lists.range(4) == [0,1,2,3])", true},
+      {R"(lists.range('abc') == [])", false},
+      {R"(lists.range(4) == 'abc')", false},
+      {R"(lists.range(4, 4) == [0,1,2,3])", false},
+      // lists.reverse()
+      {R"([1,2,3,4].reverse() == [4,3,2,1])", true},
+      {R"('abc'.reverse() == [])", false},
+      {R"([1,2,3,4].reverse() == 'abc')", false},
+      {R"([1,2,3,4].reverse(1) == [4,3,2,1])", false},
+      // lists.slice()
+      {R"([1,2,3,4].slice(0, 4) == [1,2,3,4])", true},
+      {R"('abc'.slice(0, 4) == [1,2,3,4])", false},
+      {R"([1,2,3,4].slice('abc', 4) == [1,2,3,4])", false},
+      {R"([1,2,3,4].slice(0, 'abc') == [1,2,3,4])", false},
+      {R"([1,2,3,4].slice(0, 4) == 'abc')", false},
+      {R"([1,2,3,4].slice(0, 2, 3) == [1,2,3,4])", false},
+      // lists.sort()
+      {R"([1,2,3,4].sort() == [1,2,3,4])", true},
+      {R"('abc'.sort() == [])", false},
+      {R"([1,2,3,4].sort() == 'abc')", false},
+      {R"([1,2,3,4].sort(2) == [1,2,3,4])", false},
+  };
+}
+
+INSTANTIATE_TEST_SUITE_P(ListsCheckerLibraryTest, ListsCheckerLibraryTest,
+                         ValuesIn(createListsCheckerParams()));
+
 }  // namespace
 }  // namespace cel::extensions

extensions/strings.cc

@@ -398,7 +398,9 @@ absl::Status RegisterStringsDecls(TypeCheckerBuilder& builder) {
   CEL_RETURN_IF_ERROR(builder.AddFunction(std::move(upper_ascii_decl)));
   CEL_RETURN_IF_ERROR(builder.AddFunction(std::move(format_decl)));
   CEL_RETURN_IF_ERROR(builder.AddFunction(std::move(quote_decl)));
-  CEL_RETURN_IF_ERROR(builder.AddFunction(std::move(reverse_decl)));
+  // MergeFunction is used to combine with the reverse function
+  // defined in cel.lib.ext.lists extension.
+  CEL_RETURN_IF_ERROR(builder.MergeFunction(std::move(reverse_decl)));
 
   return absl::OkStatus();
 }